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    <H1 CLASS="title">Buffer Sizes</H1>
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<H2>Overview</H2>

<P>
    The macros <CODE>BOOST_IOSTREAMS_DEFAULT_DEVICE_BUFFER_SIZE</CODE>, <CODE>BOOST_IOSTREAMS_DEFAULT_FILTER_BUFFER_SIZE</CODE> and <CODE>BOOST_IOSTREAMS_DEFAULT_PBACK_BUFFER_SIZE</CODE> can be used to configure the default sizes of buffers allocated by the Iostreams library when a <A HREF="../concepts/filter.html">Filter</A> or <A HREF="../concepts/device.html">Device</A> is attached to a <A HREF="../guide/generic_streams.html#stream_buffer"><CODE>stream_buffer</CODE></A> or <A HREF="../guide/generic_streams.html#stream"><CODE>stream</CODE></A>, or when it is added to a <A HREF="../classes/chain.html">chain</A>.
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<P>The default values are subject to change in future versions of the Iostreams library.</P>

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<H2>Headers</H2>

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  <DT><A CLASS="header" HREF="../../../../boost/iostreams/constants.hpp"><CODE>&lt;boost/iostreams/constants.hpp&gt;</CODE></A></DT>
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<H2>Synopsis</H2>

<PRE CLASS='broken_ie'><SPAN CLASS='preprocessor'>#define</SPAN> BOOST_IOSTREAMS_DEFAULT_DEVICE_BUFFER_SIZE  4096
<SPAN CLASS='preprocessor'>#define</SPAN> BOOST_IOSTREAMS_DEFAULT_FILTER_BUFFER_SIZE  128
<SPAN CLASS='preprocessor'>#define</SPAN> BOOST_IOSTREAMS_DEFAULT_PBACK_BUFFER_SIZE   4</PRE>

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